US President Joe Biden also said Putin was "responsible" for Navalny's death. (File)
Russian opposition leader Alexei Navalny was so loathed by President Vladimir Putin that the Kremlin leader refused to say his name in public.
Navalny, whose death in an Arctic prison was announced on February 16, was Putin's most prolific critic for over a decade, blasting what he called rampant corruption and refusing to back down even after being poisoned.
The lawyer-turned-politician exposed what he said were the ill-gotten gains of Putin's inner circle in investigations that drew tens of thousands onto the streets.
He leveraged the fatigue of ordinary Russians with the country's politics and his optimistic vision for a democratic Russia resonated around the country.
Before his near-fatal 2020 poisoning, Navalny had already been jailed, charged with fraud, held on house arrest, harassed and partially blinded by a chemical attack.
He died isolated, incarcerated in a Siberian prison colony, aged 47.
'Brave, principled'
His treatment by the Russian authorities drew scorn from Russia's opposition and in the West.
Nobel Peace Prize winner journalist Dmitry Muratov said Navalny had been "tortured and tormented" since his arrest in January 2021.
His wife, Yulia Navalnaya, accused Putin of ordering his killing in a final ruthless act by the former KGB agent. She vowed Putin would pay for what he had done "to our country ... to my husband."
US President Joe Biden also said Putin was "responsible" for Navalny's death.
Navalny "was brave, he was principled, he was dedicated to building a Russia where rule of law existed and where it applied to everybody," Biden said
'Putin fears me'
Even in death, Navalny's team said the Kremlin feared him as they accused Russian authorities of thwarting a public funeral.
Navalny shot to prominence in the 2010s with flashy YouTube videos exposing what he cast as systemic corruption at the heart of government.
The investigations -- which uncovered palaces, mistresses and foreign bank accounts -- embarrassed the Kremlin and brought crowds onto Russian streets. Riot police cracked down on protestors.
Blocked from running against Putin in 2018, he told AFP that Putin "fears me and he fears the people I represent."
Five years earlier he won a significant chunk of votes in a Moscow mayoral election against the Kremlin backed candidate, with no access to media and a state machine working full-throttle to stop him.
In 2020 he survived a poisoning that he blamed on the Kremlin.
Videos showed him screaming in agony from the poison while on a domestic flight in August 2020.
Navalny was flown to Germany for treatment, where tests showed he had been poisoned with Novichok, a Soviet-era nerve agent.
An investigation by several media outlets alleged that an FSB security service hit squad was behind the attack.
Navalny published a video that tricked one of the would-be assassins into revealing he had smeared Novichok onto Navalny's underwear.
Asked about the allegations, Putin said that if security services had really been behind the poisoning, they would have finished the job.
'My country'
Knowing he would face arrest, Navalny still returned to Russia in January 2021. His detention at a Moscow airport sparked large demonstrations.
Days later, Navalny's team published another investigation into a lavish Black Sea mansion they claimed belonged to Putin. The president issued a rare denial.
Eventually sentenced to 19 years on "extremism" charges widely seen as retribution, Navalny expressed frustration with being repeatedly asked if he regretted returning to Russia.
"I have my country and I have my convictions," he said in January. "I don't want to give up either of them."
'Senseless war'
For some, Navalny was tainted by an early foray into far-right nationalism and anti-migrant statements, while many Russians backed the Kremlin's portrayal of him as a Western puppet.
Behind bars, Navalny was helpless as the Kremlin launched an offensive against Ukraine, dismantled his organisation and locked up his allies.
In grainy videos from court hearings, he criticised the Ukraine campaign.
Russia, was "floundering in a pool of either mud or blood, with broken bones, with a poor and robbed population, and around it lie tens of thousands of people killed," Navalny said.
He died in a harsh Arctic prison -- nicknamed "Polar Wolf" -- in unclear circumstances.
Navalny dedicated his final social media post before his death to his wife, Yulia, who has pledged to continue his work.
He left a message for Russian people if he was killed.
"Don't give up. You mustn't, you can't give up," he said.
"All it takes for evil to triumph is for good people to do nothing. Therefore, don't do nothing."
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)